GREENWORKS 40V HIGH-POWER LITHIUM-ION BATTERY – Delivers fade-free power with no memory loss after charging. LED BATTERY FUEL INDICATOR – Integrated LED fuel indicator provides immediate feedback on state of the battery. MULTI-PROTECTION TECH – Built in battery management system (BMS) ensures complete protection for your devices. (overheat, short circuit, over voltage, over current and over charge protection). ONE BATTERY POWER ALL – Greenworks 40V batteries are compatible with 75+ Greenworks tools in the same voltage for total freedom of movement without tangled cables. 3-YEAR BATTERY WARRANTY PROTECTS YOUR INVESTMENT.